Answer :
hello!
Use the Distributive Property, which states the following:-
a(b+c)[tex]\rightarrow[/tex]ab+ac
Simplify:-
3(y+4)-7
3y+12-7
Combine Like terms:-
[tex]\sf{3y+5}[/tex]
note:-
Hope everything is clear; if you need any clarification/explanation, kindly let me know, and I'll comment and/or edit my answer :)